The present invention relates generally to dimension proportioning hand-held calculators and, in particular, to a hand-held calculator for use in electronic graphic arts proportioning.
A significant task in the graphics arts profession involves enlarging and reducing graphic material to fit within definite reproducible spacing. It will be understood by those skilled in the art, that the present invention exhibits utility for electronically determining proper proportional sizing of any piece of reproducible graphic arts. For purposes of brevity, but not to be limited by, photographs shall serve as examples hereinafter. Currently, graphic artists utilize a hand-held manually operated wheel to obtain the percentage reduction or enlargement needed for a photograph, and then rely upon a conventional electronic calculator for arithmetic computations. The conventional graphic arts proportional wheel can be inaccurate, difficult to read, and hard to interpolate. Although electronic hand-held calculators have been specially designed for specific purposes in other fields, graphic artists still use the manual method due to the lack of an electronic proportional calculator for virtually instant determination of percentage reductions or enlargements required.
Conventional hand-held electronic calculators for measurement input or output are represented by U.S. Pat. No. 4,181,959 to Iwao Tateishi issued on Jan. 1, 1980 for a combined electronic digital scale and calculator with memory, U.S. Pat. No. 4,181,960 to Iwao Tateishi and Nobuyasu Kakutani issued on Jan. 1, 1980 for a combined electronic digital scale and calculator, and U.S. Pat. No. 4,195,348 to Nobuyasu Kakutani issued on Mar 25, 1980 for an electronic digital scale and calculator with selectable programs, and U.S. Pat. No. 4,488,250 to William Lipsey and Henry Teague issued on Dec. 11, 1984 for a calculator for performing calculations in feet, inches and fractions. Conventional hand-held calculators designed for other non-measurement, but computational, purposes are represented by U.S. Pat. No. 4,486,849 to Isao Harigaya and Akihiro Yamataka issued on Dec. 4, 1984 for a computer for calculating compound interest, U.S. Pat. No. 4,446,528 to Robert Marmon issued on May 1, 1984 for a shoppers calculator.
These representative conventional electronic calculators would be either incapable of use, or extremely cumbersome in use, for determination of percentage reduction and enlargement measurements in the graphic arts industry. When faced with the task of reproducing a photograph, for example, the graphic artist begins with an original work and a space into which the original work is to be inserted in the production copy. Thus, to determine the degree of reduction or enlargement, the artist will know the original height and width dimensions, and will know either the reproduction height or width restraints imposed by the position required for the reproduction. In order to make a proper determination of reproduction sizing, the artist must know at least three of these four values. Moreover, due to the high volume of reproduction work required of the graphic artist, it has been found desirable to have a calculator capable of variable entry, calculation and display, in both decimal and fraction values, variable entry of any three of the four height and width values and automatic calculation of the percentage reduction or enlargement required, based upon the variable entry of the height and width values. It will be understood by those skilled in the art, that the prior art does not include a hand-held calculator specifically adapted for easy use in electronic graphic arts proportioning.